Crystal growing apparatus



July 22, 1947.

W. O. HAAS, JR

CRYS TAL GROWING APPARATUS Filed April 13, 1945 W 0. HAAS JA?- y' Tram/fr Patented July 22, 1947 CRYSTAL GROWING APPARATUS Walter 0. Haas, Jr., Chicago, Ill., assignor to Western Electric Company, Incorporated, New York, N. Y., a corporation of New York Application April 13, 1945, Serial No. 588,216

6 Claims.

This invention relates to crystal growing apparatus and more particularly to tanks for use in the production of piezoelectric crystals.

In the manufacture of crystals for piezoelectric devices, seed crystals have been mounted in tanks containing a solution of the salt from which the crystals are formed and the tanks are then rocked while gradually reducing the temperature of the bath to form crystals, whereby the solution adjacent the growing crystals is continually circulated or replaced with a stronger solution. In the ordinary crystal growing tanks, the ilow of the crystallizing solution is diilerent in the various areas of the tank; for example, the solution at the extreme ends of the tank rises and falls, whereas a greater amount of movement or greater flow occurs at the central portions of the tank.

It is an object of the present invention to provide a crystal growing tank in which all effective areas of the tank have substantially the same amount of flow of the crystallizing solution and to increase the ilow of solution.

In accordance with one embodiment of the invention, a crystal producing tank is provided having suitable framework placed on the bottom thereof for supporting seed crystals in a plurality of rows and directly over and in close proximity to the upper surfaces of the seed crystals there is disposed a baille, which extends to points adjacent the ends of the tank. The baille extends into engagement with the sides of the tank and has a central portion extending therefrom which is of such height that it will eifectively block the ilow of crystallizing solution from one end of the tank to the other over the top of the baille, whereby the crystallizing solution will ow in a substantially equal Volume past all of the seed crystals.

A complete understanding of the invention may be had by reference to the following detailed description wherein Fig. 1 is a sectional view through a crystal growing tank embodying the features of the present invention, together with a diagrammatic showing of mechanism for rocking and supporting the tank;

Fig. 2 is a plan sectional view taken substantially along the line 2-2 of Fig. 1 in the direction of the arrows, parts being broken away to more clearly illustrate the details of construction of those parts positioned beneath it; and

Fig. 3 is a transverse vertical sectional view taken substantially along the line 3--3 of Fig. 1 in the direction of the arrows.

In the drawings, wherein like reference characters designate the same parts throughout the several views, mechanism is shown for rocking the crystal growing tank, which comprises a crank I0, mounted upon a shaft I I, which may be driven by any suitable power driving mechanism (not shown). The crank I 0 has a link I2 pivotally connected to it and to a supporting framework I 3, on which one or more crystal growing tanks I4 may be supported. The framework I3 is, in turn, supported by angularly disposed arms I5 and I6, which are interconnected at their upper ends and are pivoted on a suitable pivot shaft I8. Thus, the tank I4 or a series of tanks mounted on the framework I3 may. be slowly rocked by imparting rotation to the shaft II.

The tank I4 has a ilange I9 formed on its upper edge for supporting a gasket 20, on which a cover plate 2l rests. A crystal supporting framework, which serves to hold a group of seed crystals 2| in position in the tank, comprises two longitudinally extending members 22 and 23, which are bent at their ends, as indicated at 24, so that they will resiliently engage the ends of the tank I4. The longitudinally extending members 22 and 23 have a plurality of channel members 25 suitably attached to them and extending transversely of the tank. Each of the channel members 25 has a plurality of blocks 26 mounted on it,

jacent to each end of the tank I4. The ends of the Y baille member 30 are spaced from the tank a distance approximately equal to the distance from the upper surface of the bottom of the tank to the lower surface of the baille 3i). The baille 30 has four brackets 3| attached to it, which are bent over at their upper ends to engage the upper surface of the flange I9 and thus support the baille 30 in the proper position. The baille 30 thus extends substantially horizontally and at its center has attached to it a vertically extending baille 32.

In the operation of the apparatus, a body of crystallizing solution 33 in the tank I4 will, when the tank is rocked, flow through the space between the end of the baille 30 and the end of the tank and since the distances between the ends of the baille and the ends of the tank are substantially equal to the distance from the bottom of the tank to the bottom of the baille, the flow of liquid will be uniform for all of the crystals. rI'he central vertically extending baille 32 will prevent fluid at the right side of it from moving over the top of the baille when the tank is rocked from the full line position (Fig 1) to the dotted line position. When the tank is rocked from the dotted line position to the full line position, the solution to the left of the baille 32 will be forced to travel under the baille 30 and thus the flow of crystallizlng solution will be maintained uniform through the entire area where the crystals 2| are growing from the size shown by full lines to that shown by the dot and dash lines 35.

What is claimed is:

1. An apparatus for growing crystals in a solution comprising a substantially rectangular tank for receiving a supply of crystallizing solution, means rockably supporting said tank, a holding means within the tank constructed to hold and support crystals above the bottom of the tank, baille means within the tank in substantially parallel relation to the bottom of the tank and in spaced relation to the ends of the tank, said baille means comprising means extending upwardly substantially centrally of the tank whereby ilow of solution from end to end of the tank above the baille may be prevented and restricted to ilow between the baille and the bottom of the tank when the tank is rocked.

2. An apparatus for growing crystals in a solution comprising a substantially rectangular tank for receiving a supply of crystallizing solution, means rockably supporting said tank, baille means within the tank in substantially parallel relation to the bottom of the tank and in spaced relation to the bottom of and to the ends of the tank, said baille means including means extending upwardly therefrom substantially centrally of the tank whereby flow of solution from end to end of the tank above the baille may be prevented and restricted to ilow between the baille and the bottom of the tank when the tank is rocked, and a holding means within the tank constructed to hold and support crystals above the bottom of thetank and below the horizontal baille means.

3. An apparatus for growing crystals in a solution comprising a substantially rectangular tank for receiving a supply of crystallizing solution, means rockably supporting said tank, crystal supports on the bottom of the tank arranged to hold the crystals above the bottom of the tank, and baille means within the tank in substantially parallel relation to the bottom of the tank and above the crystal supports and in spaced relation to the ends of the tank, said baille means includlng means extending upwardly substantially centrally of the tank whereby the solution is prevented` from flowing from end to end of the tank above the baille and is restricted to ilow from end to end of the tank between the baille and the bottom of the tank when the tank is rocked.

4. An apparatus for growing crystals in a solution comprising a substantially rectangular tank for receiving a supply of crystallizing solution, means supporting said tank for rocking movement about a pivot above the top of the tank, crystal supports on the bottom of the tank arranged to hold the crystals above the bottom of the tank, baille means within the tank in substantially parallel relation to the bottom of the tank and above the crystal supports and in spaced relation to the ends of the tank, said baille means including means extending upwardly substantially midway between the ends of said baille means whereby the solution is prevented from flowing from end to end of the tank above the baille and is restricted to flow from end to end of the tank between the baille and the bottom of the tank.

5. An apparatus for growing crystals in a solution comprising a substantially rectangular tank for receiving a supply of crystallizlng solution, said tank having a greater length than width -or height, means for supporting the tank for rocking movement about an axis parallel to the ends of the tank, crystal supports on the bottom of the tank arranged to hold the crystals above the bottom of the tank, and baille means within the tank above the crystal supports in substantially parallel relation to the bottom of the tank and in spaced relation to the ends of the tank, said baille means including means extending upwardly substantially midway between the ends of the tank whereby the solution is prevented from flowing from end to end of the tank above the baille and is restricted to ilow from end to end of the tank between the baille and the bottom of the tank when the tank is rocked.

'6. An apparatus for growing crystals in a solution comprising a substantially rectangular tank for receiving a supply of crystallizing solution, said tank having a greater length than width or height, means for supporting the tank for rocking movement about an axis parallel to the ends of the tank, crystal supports on the bottom of the tank arranged to hold the crystals above the bottom of the tank, baille means in the tank comprising a main baille disposed above the crystal supports in parallel relation to the bottom of the tank and extending from side to side of the tank and with the ends of said baille spaced from the ends of the tank a distance substantially equal to the distance of the main baille from the bottom of the tank, and an auxiliary baille extending upwardly from the main baille substantially midway between the ends thereof and extending from side to side of the tank, said baille means serving to prevent the flow of solution from end to end of the tank above the main baille and to insure the ilow of solution between the baille and the bottom of the tank when the tank is rocked.

WALTER O. HAAS, JR.

REFERENCES CITED UNITED STATES PATENTS Name Date Kjellgren May 2, 1933 Number 

